Safety device for hydraulic apparatus.



No. 660,382. 1 Patented 0ct.'23,.-|900. F. LAMBERT.

SAFETY DEVICE FOR HYDRAULIC APPARATUS. (Applicaticn filed. Apr. -5,1899.)

{No Model.) 2 Sheets-Sheet I.

fixwzc ZZMJ I BY P i B Y A L F SAFETY DEVICE EQR: LEYBJBAUIHQ APPARATUS.

(Appligafiigm l Ayn. 65, 118/980 2 Sheets-Sheet 2.

(No Model.)

WITNESS ES ATTORNEY been relieved,

TED STATES PATENT OFFICE FRANK LAMBERT, OF NEW YORK, N. Y.

SPECIFICATION forming part of Letters Patent No. 660,382, dated October23, 1900.

Application filed April 5,1899- oerial No. 711,775. \NO m del-l I To allwhom it may concern/.5

Be it known that I, FRANK LAMBERT, a citizen of the United States, and aresident of New York, (Brooklyn,) Kings county, State of New York, haveinvented Safety Devices for Hydraulic Apparatus, of which the followingis a specification.

My invention relates to apparatus such as water-meters or the like,which, through excessive internal pressure developed by expansion whenthe contents freeze, will burst, or the parts will become so distortedthat leakage occurs.

The object of my invention is to provide means whereby the apparatuswill not be injuriously affected by accidental excessive pressure, andleakage will be prevented at the time of or after this excessivepressure has I accomplish this object by so constructing the apparatusthat before the internal pressure becomes great enough to break orpermanently deform the water-receptacle its cubic liquid content mayincrease enough to provide ample room for the expansion into ice of theliquid confined in the apparatus. This is done by means of the'safetydevices herein shown and described as applied to a Well-known form ofhydraulic apparatus- In the accompanying drawings, Figure 1 is across-section through the center of a watermeter, showing my improvedsafety device applied thereto. Fig. 2 is a plan view of a detail of thesafety device. Fig. 3 is a sectional view of a modified form of safetydevice, and Fig. 4 is a detail view of another modification.

Referring to Fig. 1, the meterhere shown comprises a pressure casing orshell 1, provided with water-inlet 2 and outlet 3, a measuring-chamber4E, and suitable indicating and registering mechanism forming no part ofthe present invention.

The measuring-chamber at is secured within the pressure-shell 1 in sucha manner that Water entering the inlet 2 may pass around, above, andbelow the measuring-chamber, through which the water must pass before itreaches the outlet 3, this latter leading directly from themeasuring-chamber. When the water in such a meter comes to or near tothe freezing-point, the coldest particles have a tendency to rise to thetop, and the water near the upper part of the receptacle or shellbecomes generally frozen first, the ice gradually thickening downward.As long as the openings of the pipe connections are not frozen theexpansion due. to the water freezing does no damage, there simply beingback pressure in the inlet-pipe or increased pressure in theoutlet-pipe, (if there is no leakage in the various fittings,) or both.However, when the ice is thick enough to reach a point below or at thelowest level of the inlet 2 and outlet 3, or, in other words, these havebeen clogged up by ice and the water confined in the lower part of theshell freezes, there is no place for the increased volume to forceitself, and the shell will either burst or become so distorted that itwill be put out of joint and leak, rendering the apparatus inoperati ve.

It'is a known fact that ice submitted to pressure will partly melt andconform itself to the shape of the receptacle in which it is compressed.This occurs in water meters such as shown in Fig. 1 from the moment thepipes are frozen or the ice is thick enough to reach the lower edge ofthe ports. Up to this point the ice has freely formed, molding itself tothe interior free space of the casing without any pressure other thanthe normal internal Water-pressure; butfrom this momentuntil the waterin the apparatus is entirely frozen considerable internal pressure isdeveloped and the portion of ice above the lowest level of the portswill be compressed upward, carrying with it the measuring-chamber 4,which will be found afterward to have been distorted. This is due to thefact that the great force applied between the lower face of the chamber4' and the lower interior face of the shell, which must be very rigid,acts against the chamber with a tendency to lift it upward with the samepressure that it acts on the bottom of shell to force it outward.

The pressure in Water-supply pipes in general is normally less than twohundred pounds per square inch; but the pressure may rise to threehundred, and sometimes much more, depending upon the rapidity with whichthe water-flow is shut ofi, causing water-hammer. Consequently the shellor casing of the meter is designed to withstand a pressure considerablymore than the normalsay eight hon dred to one thousand pounds\vithontbeing permanently deformed.

Referring to Patent No. 375,023, granted to John Thomson and myself onDecember 20, 1887, it will be seen that the bottom of the meter-casingis formed slightly curved inward. This concave portion tends to flattenor be pushed outward under excessive internal pressure; but thedistortion of this portion will act on the entire shell, or at least onthe joints and the bolts that unite the lower portion with the upperportion, to permanently deform the parts,causingleakage at thejoints.The present invention is an improvement on this construction. Instead ofmaking the entire lower portion of the meter of material capable ofwithstanding the maximum pressure, as in the above-mentioned patent, Iform a safety portion, preferably below the lowest level of the openingof the-pipe connections, of material that will yield before thepredetermined maximum pressure of the rest of the shell is reached.

As shown in Fig.1,the shell 1 may be formed with an aperture which isclosed by a safetypiece 5, of lead, tin, copper, metal alloys, or othersuitable material and of such thickness that it will be pliable under a'pressure less than that necessary to permanently deform the rest of theshell. For instance, in meters capable of safely standing one thousandpounds of pressure the safety device may be made capable of yieldingunder two hundred and fifty or three hundred pounds of pressure.

The safety-piece 5 is secured to the shell 1 by the ring 6 and bolts 7,screwed into the blind threaded holes in the lugs 16 of the shell.Preferably I make this piece with a bowl-shaped port-ion protruding inwardlyand normally lessening the capacity of the shell. This inwardly-bulging portion preferably decreases in thickness toward itscenter, whereby when from expansion or otherwise the pressure in themeter exceeds the resistingpower of the safety-piece its central portionwill yield first and gradually be forced outward, assuming,approximately, a shape such as indicated by dotted lines a, b, c, d, or6, Fig. 1, according to the pressure exerted, thus increasing the normalcubic water content of the meter suflicient to prevent damage. In otherwords, the capacity of the meter is increased, while the shell ismaintained watertight.

If after one or more partial or total freezings the bowl-shaped portionof the safetypiece 5 has been forced outward considerablysay, forinstance, as represented in dotted lines a, d, or ethe ring 6 may beremoved and the safety-piece reversed, so that the central portion againprotrudes into the meter.

By making the opening in the ring 6 slightly smaller than the aperturein the shell 1, if the bowl-shaped portion of the safety-piece has beenforced by internal pressure to the extreme outer shape shown at c thisinverted bowl will be small enough in diameter to be easily insertedinto the aperture in the shell when the safety-piece is reversed.

The inner circumferential edge of the ring 6, next to the safety-piece5, is preferably well rounded to prevent the safety-piece from bendingat a sharp angle, and thereby increasing the tendency to cut or break.To insure a good joint, a packing-ring or gasket 8 is preferably placedbetween the faces of the safety-piece and the shell 1, although thisgasket may be dispensed wit h when the safety piece is made of very softmaterial, such as lead.

To provide for expansion of water into ice, the safety-piece may becalculated for the limit of safety, to increase by its deformation thecubic water content of the apparatus one-eleventh of its normalcapacity, which is the approximate maximum limit of expansion of waterwhen solidified into ice. By means of this construction the water in themeter is always confined-that is, the meter remains water-tight-thuspreventing leakage in case the water is only partially frozen or a thawoccurs. This is a Very important factor in an apparatus of this kind,which in winter will often freeze and even thaw out unexpectedly andwithout attracting any ones attention, thus often causing considerabledamage by the water before it is known and the water shtit off. It willthus be seen that the safety device forms a protection to the rest ofthe apparatus against damage from any undue internal pressure from anycause, as the safety-piece will give way before the predetermined safetypressure of the apparatus is reached.

Fig. 3 represents a modification whereby when the safety-piece has beenforced outward by accidental extra pressure it will be automaticallyreturned to its normal position when the normal pressure in the meter isresu med. In this modification the safety-piece may be of uniformthickness, and a thin sheet of copper will suffice to keep a tight jointand prevent leakage; but I do not limit myself in any case to anyparticular material or form.

Referring to Fig. 3, the safety-piece 9 is secured to the shell 1- bymeans of the outer flange or ring 10 of the flanged cylinder 11 andbolts 7, and a thick washer or block 12, of soft rubber or the like, isheld against the safety-piece 9 bya spring 13, one end of which bears onthe inner flange 14 of the cylinder 10, while the other end presses therubber washer 12 and the safety-piece 9 upward. The force or tension ofthis spring 13 is calculated to resist a pressure greater than thenormal water-pressure in the meter, but to yield under a pressure lessthan is necessary to deform the shell proper. Therefore When theinternal pressure in the meter exceeds the resisting-power of the spring13 the safetypiece 9 and the washer 12 are forced outward, compressingthe spring 13. As soon as the pressed up or down wi h the safety-piece.

pressure in the meter diminishes the spring 13 reacts and forces thewasher or block 12 and the safety-piece 9 back, so that when theinternal pressure again becomes normal the safety-piece has againresumed its normal shape, as shown in Fig. 3. The tension of the springis calculated to safely overcome the resistance of the normalwater-pressure plus the resistance to deformation of the material of thesafety-piece and block 12.

The spring 13 may be made of steel wire of variable cross-section, andattention is called to its peculiar form, which gives it an increasingresistance to compression from its center outwardthat is, the resistanceof the spring is weakest when its central coils are depressed andstrongest when the external coils are depressed. This variableresistance is madeto compensate for the internal pressure, which presseson the safety-piece with variable effect at its different portions, inaccordance with its diameter, whereby the entire system under pressure(if the resiliency of the spring is properly calculated) will tend todepress the safety-piece at the center first and near the peripherylast;

Instead of the wire spring 13 I may use a spring 15, Fig. 4, formed bycoiling a flat strip of metal varying in width, the narrowest portionbeing at the center and the widest part at the outer coils, so that theresistance of the spring to compression will be less at the center thannear its outer diameterthat is, in accord with the effect of theinternal pressure acting on the safety-piece, as before explained.

The washer l2 prevents any corrugations or sharp bends or kinks formingon the safetypieee, might happen if this latter were resting directly onthe coiled spring 13 or 15, the washer following the uneven contour ofthe top of the spring. This washer also acts to cushion thesafety-piece.

The outer edge of the washer 12 enters a recess in the flanged cylinder11, whereby it is prevented from getting out of place when Thesafety-piece may be formed of a plurality of layers of the samematerial, or of various materials combined. For instance, if lead isused for the safety-piece proper, a thin sheet or layer of copper may beplaced on one or both sides thereof to protect it againstcorrosion,which might change its strength or flexibility.

I claim as my invention 1. In a water-meter, apressure-shell, the saidshell being provided with an aperture, a reversible safety-piece closingsaid aperture and adapted to yield under a water-pressure less than thatnecessary to deform the shell.

2. In a water-meter, a pressure-shell, the said shell being providedwith an aperture, and a reversible safety-piece closing said apertureand provided with a bowl-shaped portion protruding into the interior ofthe meter and adapted to be inverted by a water-pressure that will notdeform the other parts of the meter.

3. In a water apparatus, a shell having an aperture, a reversiblesafety-piece closing the said aperture and normally protruding into theinterior of the apparatus, but capable of having its form reversed by aninternal pressure that will not deform the shell, and means to limit thediameter of the outward bend given the said safety-piece by theexcessive pressure to a size less than the diameter of the saidaperture.

4. In a water apparatus, a shell having an aperture, and a safety-piececlosing said aperture and adapted to yield under pressure less than theone required to deform the said shell the said safety-piece decreasingin resistance from the circumference toward the center.

5. In awater apparatus, a shell, having an aperture, and a safety-piececlosing said aperture and adapted to yield under a water pressure lessthan the one required'to deform the said shell, the said safety-piecedecreas ing in thickness toward the center.

In testimony whereof I have signed my 'name to this specification in thepresence of two subscribing witnesses.

FRANK LAMBERT.

